Spark plug



I VEN ORI' ATTORNEY Jne 16, 1925.

, L. MORRISON ET AL SPARK PLUG Filed July 13, 1923 MIM/Vago@ Patented J une 16, v1925.

UNITED-'STATES PATENT OFFICE.

LEWIS MORRISON AND THOMAS L. MORRISON, OF EAST LEAVENWORTH, MISSOURI.

SIARK PLUG.

Application filed July 13, 1923. Serial No. 651,314.

To all whom t may concern:

Be it known that we, LnwIs MORRISON and THOMAS L. MORRISON, citizens of the United States, residing at East Leavenworth, in the county of Platte and State of Missouri, have invented new and useful Improvements in Spark Plugs, of which the following is a specification.

This invention relates to spark plugs such as used in internal combustion engines, and

an Object of the invention `is to provide a` spark plug which is designed to eliminate to material extend ignition troubles caused by the fouling of the sparking points, the said plug comprising a protecting cup structure which encloses the sparking points and protects them from accumulation of oil, thereon, consequently increasing the longevity and efficiency of the spark plug.

Another object of the invention is to provide a novel simple construction for locking the normally removable protecting cap to the bottom of the shell of the spark plug to prevent accidental disconnection' of these parts.

Other objects of the invention will appear in the following detailed description taken in connection with the accompanying drawings wherein Fig. 1 is a side Lelevation of the improved spark plug.

Fig. 2 is a longitudinal section through the spark plug.

Fig. 3 is a cross section on the line 3-3 of Fig. 1. p

Fig. 4 is anenlarged detail section taken on the line 4-4 of Fig. 1.

Fig. 5 is an enlarged detail cross section taken on the line 5-5 of Fig. 1.

Referring more particularly to the drawings, the improved spark plug comprises the body shell l, into which the porcelain 2 eX tends. The central electrode 3 extends centrally through the porcelain 2 and terminates inwardly of the lower housing in the body shell 1. The extreme lower end of the body shell 1 is reduced in diameter, to provide the connecting fiange 4-which is 'externally screw threaded and to which the protecting cup o is threadedly connected.

The protecting cup 5 has a sparking point 6 carried thereby and extending vertically thereof axially of the cup and in alignment with the central electrode 3. The facing ends of the central electrode 3 and the spark- 55 Ving point 6 are spaced slightly to provide a sparking gap as indicated at 7. The body shelli is provided with a plurality of relatively large circumferentially spaced transverse openings S in lateral alignment with the sparking gap 7 which openings are designed to permit the entrance of the combustible gases into the spark plug for igni tion by an electric spark jumping the gap 7..

iter the cap 5 is threaded upon the couh pling flange 4 of the body shelll l it is drilled' transversely to provide the openings 9 which extend through the cup 5 andthe flange 4 andv communicate with the interior of the body shell below the openings 8.

The cup 5 is securely locked to the shell 1 by a locking strip 10 which is inserted through a slot out through the cup 5 and sleeve V1 at the point where the upper end of the cup fits against the annular shoulder 11 formed by the reducing of the body shell to provide the connecting flange 4. I{By particular reference to Figs. 4 and 5 of the drawings it will be noted that the slot 12 does not penetrate into the interior Opening in the body shell or cup. The ends .13 of the locking strip 10 are bent back and engage the outer surfaces of the cup and body shell Vas clearly shown in Figs. 1 and 5 of the drawings for holding the locking strip against accidental movement and securely locking the cup 5 upon the body shell.

It is, of course, to be understood that the invention may be constructed in other manners and the parts associated indifferent relations and, therefore, we do not desire to be limited in any manner except as set forth in the claims hereunto appended.

Having thus described our invention what we claim is 1. A spark plug comprising a body shell, a protecting cup at the lower end of the body shell, said protecting cup and body shell provided with registering recesses forming a slot, at their engaging portions, 100

and a looking strip inserted through said recesses, the ends of said looking strip being bent back and engaging the outer surfaces o the body shell and oup.

2. A spark plug comprising a body shell, a protecting cup attached to the lower end of the body shell and a looking strip engaging the body shell and Cup, the ends of said looking strip being bent back and engaging the outer surface of the body shell and oup. 10

In testimony whereof We affix our signatures.

LEWIS MORRISON. THOMAS L. MORRISON. 

